On a December day four years ago, I went to meet Wangari Maathai. I had been asked to interview her as part of a series on exceptional women but even in a list containing such luminaries as Liberia’s first female president, Ellen Johnson Sirleaf, Wangari Maathai’s name jumped out. Her story is one that has parallels with the other great name so tragically lost to the world this week – Apple’s Steve Jobs. Like Jobs, Maathai was a visionary who transcended humble roots and went on to do wonderful things. And as Jobs did, she was also one of the few people who can be said to have truly changed the world. Born in the 1940s to a peasant family in the tiny village of Ihithe in Kenya’s central highlands, Maathai’s career spent defying the odds got off to a flying start when she was sent to primary school at the age of eight. Unusually for girls at that time, she went on to second...